1. Technical Field
The present invention relates to a printing apparatus and a control method. More specifically, the invention relates to a printing apparatus configured to print images on a printing medium by discharging ink while transporting the printing medium and a method of controlling the printing apparatus.
2. Related Art
A printing apparatus configured to print images on a printing medium by discharging ink from nozzles might suffer from discharge failure caused by increased viscosity of ink or the like occurring in nozzles during downtime. When the discharge failure occurs, the quality of printed images is deteriorated, and hence the printing apparatus is provided with a function to clean the nozzles for the purpose of solving the discharge failure. However, the cleaning is a time-consuming job and, in addition, a large amount of ink is consumed in many systems. Therefore, it is not preferable to execute the cleaning excessively.
In JP-A-10-119307, a detecting method for optically detecting ink discharge failure is disclosed. In JP-A-2000-272116, an ink jet printer configured to detect automatically a defect of ink nozzles from a printed sample is disclosed. In JP-A-2005-262867, detection of discharge failure by an induced current generated when charged ink adheres to a sensing unit formed of a conductor is disclosed. These technologies allow users to know whether execution of the cleaning is needed or not. In other words, the cleaning is executed only when it is necessary, and hence excessive execution of the cleaning is prevented.
However, in the case of a printing apparatus configured to print high-quality images at high speed, a printhead tends to be upsized due to the increase in number of nozzles. Therefore, the time required for the cleaning is increased and, in addition, the quantity of ink to be consumed by the cleaning is also increased.